Gout is one of the most common forms of arthritis affecting about 8 million Americans and is the most common inflammatory arthritis in men after the age of 40.
So how does it develop?
Gout is a metabolic disease. Under normal conditions, the production of uric acid (UA) that comes from the breakdown of purines found in many foods is balanced by elimination of UA. People with gout have much more UA in their system. This is a result of either inability to get excrete UA through the kidneys or to overproduction of UA, or both. In reality 90 per cent of gout is due to inability to excrete UA through the kidneys rather than overproduction.
When the level of UA exceeds a certain threshold, crystals of monosodium urate deposit in joints and other areas. The deposits of crystals can be influenced by other factors than just the level of uric acid in the system. These factors include dehydration, the amount of acididity, and temperature.
For example the solubility (ability to stay dissolved) of uric acid drops with temperature decline. This Is one of the explanations why attacks of gout tend to occur in the feet.
Attacks of gout can occur when there are fluctuations in the systemic pool of UA caused by drops in temperature, dietary intake of foods high in purines, starting treatments to lower uric acid, or dehydration.
When monosodium urate crystals (MSU) accumulate in joints, they trigger acute inflammation which leads to attraction of white blood cells to the area, release of chemicals that enhance inflammation, and the eventual development of an acute case of gout.
Gout attacks are characterized by swelling, heat, redness, and intense pain.
Even though the acute attack can be treated with relief of symptoms, MSU crystals are still present inside the joint and cause low-level inflammation. Microscopic analysis of joint tissue during the intercritical phase has shown the presence of large deposits of inflammatory material and MSU crystals.
As time passes, and gout continues, monosodium urate crystals and the attendant inflammation they cause lead to significant damage to joints and internal organs like the kidneys. The typical finding on x-ray is impressive erosions involving joints.
With disease progression, the time between acute attacks- termed the intercritical phase- no longer is a pain-free period. The patient will soon enter the phase of chronic gout where joint destruction and significant kidney damage will occur.